Which of the following is a part of the nomenclature of a semiautomatic pistol?

The muzzle and barrel of a semiautomatic pistol are essential components that contribute to its function and overall design. The barrel is the long tube through which the bullet travels when the gun is fired, and the muzzle is the front end of the barrel where the bullet exits. Understanding the nomenclature of a semiautomatic pistol includes recognizing these parts, as they play crucial roles in the firearm's accuracy, performance, and safety.

The other components mentioned, while important in the context of firearms, do not specifically belong to the nomenclature of a semiautomatic pistol in the same way. For example, the ammunition magazine is a critical part for feeding cartridges into the chamber, but it is more about the firearm’s operation rather than a specific nomenclature term. A trigger lock is an accessory designed to enhance safety by preventing the trigger from being pulled, which is a separate consideration from the actual structure and terminology of the pistol itself. The safety catch is a mechanism that prevents accidental firing but is again not a specific part of the nomenclature that identifies the basic components of the pistol.